Showing papers in "Chemical Physics Letters in 1987"

TL;DR: In this article, an algorithm is described for determining reaction paths between two known structures with many degrees of freedom, using first-derivative techniques to optimize the entire path between the two end forms subject to certain constraints.

TL;DR: In this article, a reduced variational space method is presented for analyzing hydrogen bonding interactions in terms of Coulomb and exchange, polarizability, and charge-transfer components, which relies on the use of SCF optimized monomer orbitais in dimer calculations.

TL;DR: In this article, a mass-selected negative carbon clusters extracted from a pulsed supersonic beam are reported for the UPS data and electronic structure calculations strongly support the spheroidal shell model for C 60.

TL;DR: In this article, the σ 0 values for the 13 C nuclei in this work have been determined absolutely and compared with calculated values, except where low-lying n → π ★ transitions contribute significantly to the paramagnetic shielding.

TL;DR: In this paper, the C-H stretch modes of monolayers of methanol and pentadecanoic acid adsorbed on glass and water using sum-frequency generation were observed.

TL;DR: In this article, it was shown that transient free radicals trapped in micelles exhibit electron spin resonance (ESR) spectra with "antiphase" lineshapes, i.e. lines with their low-field halves in emission and high-field half in absorption.

TL;DR: In this article, a magnetically focused time-of-flight photoelectron spectrometer was used to obtain UPS spectra for mass-selected negative cluster ions of silicon and germanium in the 3-12 atom size range.

TL;DR: In this paper, the second-order Moller-Plesset calculations to second order have been carried out on the ten-electron systems Ne, HF and H 2 O with a new functional, including r 12 -dependent pair correlation functions, which takes care of the correlation cusp.

TL;DR: In this article, the first numerical results using two extended coupled cluster models that include triple excitations were reported and compared to full CI for several systems, and the results showed that these methods are superior to CCSDT-1 when the reference function is poor, such as in bond breaking cases.

TL;DR: In this paper, positive and negative ions of the type C2n (30⩽2n⌽210) and C 2n+1Hx (x⌾2), called polyhedral ions in this letter, have been found in hydrocarbon flames.

TL;DR: In this paper, the mean free path of a Xenon adsorbed on various zeolites was determined by computing the dependence of the chemical shift σ on the free path.

TL;DR: In this paper, the dynamics of molecular isomerizations that involve major charge redistributions were studied using picosecond lasers and the usual assumptions that the isomerization barrier is independent of temperature and constant within a solvent series were found to be incorrect due to solvent polarity effects.

TL;DR: In this paper, a new type of aluminium in hydrothennally treated Y and ZSM-5 zeolites has been detected by high-field 27 Al NMR, using very fast sample spinning and two-dimensional NMR spectroscopie techniques.

TL;DR: Kinetic and singlet-triplet data were used to treat the mechanism of electron transfer for BChl*_2-BChl-BPh in bacterial photosynthetic reaction centers.

TL;DR: In this paper, an interface-selective probe of molecular vibrations is used to obtain vibrational spectra of molecular monolayers on metal and semiconductor surfaces, which obey electric dipole selection rules: vibrational modes must be both Raman and infrared active to show sum frequency resonances.

TL;DR: In this paper, a multireference coupled-cluster method using an incomplete model space is applied to the direct calculation of the difference energies of formaldehyde, which is made of a reference space composed of particle-hole excited configurations built from a set of active orbitals.

TL;DR: In this paper, the femtosecond time resolution of the experiment allows the study of pronounced high-frequency beat phenomena up to 10 THz, and the frequency difference between vibrational modes separated by more than 300 cm−1 may be determined with high precision.

TL;DR: In this article, the electronic structure and spectra of the icosahedral C 60, "follene-60" were examined by use of the CNDO/S method.

TL;DR: In this paper, it was shown that the temperature-activated optical dynamics of the excitonic J-bands can best be explained by invoking the presence of a pseudo-localized degree of freedom of ≈9 cm-1.

TL;DR: In this paper, it is argued that P+I− may be too short-lived to give rise to significant polarization and that the experimental spectrum is consistent with the rapid formation of a spin-correlated secondary radical pair.

TL;DR: In this paper, large scale Hartree-Fock calculations were performed to estimate the thermodynamic stability of the recently proposed spheroidal C60 molecule (Buckminsterfullerene) relative to a sixty-atom single sheet of graphite.

TL;DR: In this article, the authors used the Z vector, the solution of a set of perturbation-independent CPHF-like equations, to rotate the molecular-orbital (MO) variations in the reference configuration.

TL;DR: In this paper, it was shown that non-nuclear attractors may be typical of the alkali metals and are responsible for their characteristic properties in charge distributions of both Li and Na atoms, and the properties of the resulting pseudo atoms as determined by the theory of atoms in molecules are similar for both sets of clusters.

TL;DR: The Moller-Plesset partitioning of the many-electron Hamiltonian is generalized for arbitrary open-shell and multiconfigurational SCF reference states.

TL;DR: In this paper, a Monte Carlo evaluation of integrals of the form exp[i S (x )] that occur in the Feynman path integral representation of the time evolution operator, exp(−i Ht/h ).

TL;DR: In this paper, the rotational and centrifugal distortion constants within a Watson S -reduced Hamiltonian are determined and interpreted in terms of a centrosymmetric slipped parallel structure.

TL;DR: In this paper, a non-Cartesian coordinate system was developed which permits the vibrational motions of Buckminsterfullerene to be expressed in terms of four force constants, and a 180 × 180 matrix was then derived which, when diagonalized, yields the complete vibrational spectrum.

TL;DR: In this paper, the 31P spectra of several inorganic phosphates have been examined both in the crystalline and the glassy states, and the parameter (Zeff/r)q clearly demarcates ortho-, pyro- and meta-phosphates in terms of the chemical shifts.

TL;DR: The equilibrium geometries of selenium clusters Se 3 to Se 8 have been calculated using a parameter-free density functional method, and the most prominent low-energy structures are found using combined molecular dynamics and simulated annealing techniques as mentioned in this paper.

TL;DR: In this paper, the authors assign the higher energy band to the 1e g →a lu transition of the radical macrocycle (Pc − ) while the lower energy band may be related to an intramolecular charge transfer from one macrocyclic ligand (pc 2− ) to the other (p c − ).